Structure of pneumatic tire covers

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION In FIG.
1, which shows half of a pneumatic tire carcase symmetrical about the plane XX", are indicated the tread 1 of the tire provided with grooves 2, the rubber layer of the side wall 3 and the peripheral reinforcement formed by the two plies 4 and 4'.
Said peripheral reinforcement for the stabilization of the tread of the tire is superimposed on the carcase and is formed by plies of metal threads, or of another kind threads, placed so as to form angles from 10.
degree.
to 25.
degree.
with respect to the plane of longitudinal symmetry.
In the Figure are also indicated: with T the inner structure (or shell) (drawn with a continuous line), formed by a ply whose threads of aromatic polyamide are arranged in radial planes; with L an inner layer, with respect to the ply T, of a mixture of elastomer for protection from the side of the inner tube; with S and P (drawn with a broken line) the outer stabilizing structure (or shell), able to withstand those forces directed along the axis of rotation of the tire which tend to flex it laterally.
Said plies of the outer structure are formed of materials other than aromatic polyamide and in the specific case are formed by the polyamide known commercially as "nylon".
The direction of the threads of each ply of the outer structure forms an angle of 18.
degree.
with the radial planes, and in addition the direction of the threads of the ply S crosses that of the threads of the ply P.
All the plies of the inner and outer structures are anchored to the bead wire C by folding back the free edges to form flaps which end with their free edges staggered and more particularly, ply T at T1, ply S at S1 and ply P at P1.
In FIG.
1 is also indicated: with R a filling of elastomeric mixture to shape the bead.
In the case under discussion ply T is formed by threads in aromatic polyamide having a count of 1670.
times.
3 decitex, breaking load of 75 Kg, elongation at 23 Kg (i.
e.
equal to 1/3 of breaking load) of 2.
81